What is the uncanny valley?

Japanese roboticist Masahiro Mori proposed the concept in 1970. He observed that as robots become more human-like, our affinity for them increases, but at a certain point, just before they become indistinguishable from real humans, our response suddenly turns to revulsion. This dip in comfort is the “uncanny valley”. A cartoon character can be endearing, but a hyper-realistic digital human with slightly wrong eye movements or skin texture feels creepy. The effect applies to CGI characters in films, humanoid robots, prosthetic hands and even some dolls. As CGI and robotics improve, the valley is gradually being crossed, but it remains a challenge in animation, gaming and AI.